[XutvJet]

I'm curious to hear from those that changed their plugs to one step colder plugs and/or reduced the gap on their OTS Stage II flashed and piggyback modified EWG N55s. I'm not talking about N55s running custom tunes, meth, ethanol, different turbos, etc.

I'm currently at 45K miles on my 2016 M235, stock plugs, HJS Euro 6 DP, FTP CP, and Dinantronics Stage 2 piggyback. This combo is good for around ~380whp/400wtq on a Dynojet or roughly MHD Stage 2 power. I've run this combo for about 7 months now. Prior to Stage 2, I ran in Stage 1 mode for about 5 months (w/DP) and prior to that the Dinan Sport (without and then with the DP). The car has never had a driveability hiccup or misfire. The car has always been run on 93 octane.

From what I gather on the BMW forums, the plug and gap changing direction when adding power originally came from the N54 crowd. The N54 has well known issues with misfires in stock form and more so in modified form. The reason being the coil packs sucked, the injectors sucked, and the OEM plugs were too HOT! With the N55, BMW went with far more reliable coil packs and injectors and one step colder plugs. You rarely hear of coil pack and injector issues in older and modified N55s. Misfires are still common and many attribute it to the spark plugs.

There's no doubt that more power is hard on plugs. Add power and you should expect life to be shortened. I totally agree that if you've got a modified N55, you probably should be changing plugs every 30K or so to be safe. The one step colder and/or change in gap recommendations by many on the forums though is perplexing because it sure seems like those that go with colder and/or regapped seem to have more misfires. Am I reading this wrong? What may apply to the N54 may not apply to the N55.

Are colder plugs and reduced gaps really necessary with the more common OTS Stage II setup on the EWG N55? The consensus is hit and miss.

Were misfires addressed with a change to colder plugs and/or reduced gap?

When you made the change, were the OEM plugs worn out and perhaps were the actual cause of the misfire and not a heat range or gap issue?

Why aren't more people running the M2(N55 and S55)/3/4 plugs if they want something capable of handling more heat from mods? Wouldn't that make more sense?

[Liandri]

Very curious to hear some answers on this as well

[Pray for Mojo]

The one step colder N20 plugs were originally recommended by BM3 and I believe it's because the N20 stock runs roughly the same boost levels as Stage 2 N55s. BMW obviously had engineering reasons for putting 1 step colder at higher boost. A gap smaller than .022 or .024 is probably not required without big turbo ect.

I tuned my car at roughly the same mileage you did, figured the stock plugs would be tired soon so I might as well switch, have had 0 misfires in 20k with 1 step colder at 0.022.

[Dylan86]

Originally Posted by Pray for Mojo

The one step colder N20 plugs were originally recommended by BM3 and I believe it's because the N20 stock runs roughly the same boost levels as Stage 2 N55s. BMW obviously had engineering reasons for putting 1 step colder at higher boost. A gap smaller than .022 or .024 is probably not required without big turbo ect.

I tuned my car at roughly the same mileage you did, figured the stock plugs would be tired soon so I might as well switch, have had 0 misfires in 20k with 1 step colder at 0.022.

This ^

Also the S55 plugs run the same #'s, and higher boost.

[Trofeo]

What about about folks with 2+ upgrades: i.e. HPFP, meth injection and a more aggressive tune such as Cary's? Essentially in the ~500whp zone.

[Jnat]

No authority here just what i've done on many modified cars. One step colder plugs are recommended (not mandatory) when adding power due to cylinder temperatures and pressure. i believe the thought is one heat range lower for every 75 hp or more. Again, recommended. I did it on my N54 and now N55, i've had no issues.